General Article

Problems With Foundations Constructed on Sandy Loam Soil and How to Identify, Prevent, and Rectify


A soil composition primarily known as “sandy loam” is a mixture of sand, clay, silt, and organic matter. Sandy loam is a very stable soil that shows little change with the increase or decrease of moisture and can easily support a slab foundation. Problems occur if the builder added fill to the substrate that was of a different soil composition. If this added fill consists of a higher clay content then expansive conditions can occur if balanced moisture is not maintained around the foundation

Let us identify some readily apparent observations. If your interior doors are difficult to close and you are observing cracks in the sheetrock, or cracks in exterior siding or perhaps masonry; then you may be experiencing foundation problems. Whether your house was built on pier and beam or on a concrete slab foundation these problems can occur.

The most common cause of these problems is due to the perimeter of your foundation being unequally saturated with moisture. Whenever there is a period of several months with minimal rainfall, you will have a variation of moisture saturation in the soil around the perimeter of your foundation. The out of balance moisture will cause stress and movement and if one part of your house settles more quickly than another then you will have problems.

The older your foundation, say twenty or so years, the more you will need to apply the following simple preventive procedures. By doing so you will get many more years of trouble free enjoyment from your home.

The simplest method of prevention and control of this problem is a timed irrigation system around the perimeter of your home that activates three or four days a week for 15 or 20 minutes each day. A well maintained gutter and down spout system is crucial in order to keep balanced moisture around your foundation.

Observe the drainage around your home as improper grading often results in future foundation problems. Grading should always divert water away from your home so as to not allow water to puddle around the foundation. Surface grading needs to be sloped away from the foundation at 5% or greater pitch for the first ten feet from the foundation.

Another worry with sandy loam is erosion, also a good reason you want to make sure you have good drainage around your foundation. Puddling saturates the sand causing it to shift around creating movement which is known as a floating slab.

If your foundation is experiencing excessive settling you must correct this problem as soon as possible because in wet weather the ground will swell and in dry weather it will shrink causing constant stress on the foundation. Over a number of years this recurrent movement will cause extensive damage and will be very costly to repair.

If your house is on pier and beam, a house leveling company merely raises your house, levels it, then makes adjustments to the building blocks it is resting on. If you have a concrete slab you may have to turn to slabjacking to correct damage. The is accomplished by digging footings every 6 to 7 feet under bearing beams and compressing concrete cylinders down to a competent soil layer.

House leveling and stabilizing will need to be completed professionally and inspected by a registered engineer.

After the identification and repairing of the foundation settling problems, hasten to take preventive action as suggested in this article in order to avoid further damage.